Re: Differences between man-pages and libc manual safety markings

[Alexandre Oliva <aoliva-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Oct 27, 2014, Mark Thompson <mrt-W77v16wj1OVeoWH0uzbU5w@public.gmane.org> wrote:

> Now suppose we have such an implementation.  Consider two distinct
> threads copying the same thing which is longer than a cache line

"/dev/tty" (the constant string copied in the case at hand) is not
longer than a cache line (right? :-), so while your case is compelling,
it doesn't apply.

> Since strcpy will always write at least one byte, can you really argue
> that adding "*dest = 0;" to the beginning of a strcpy function is
> always a bad thing?

Now, this one is compelling *and* fitting IMHO.

Of course we could rule this out in glibc, but should we?  Maybe not.

So I guess we're better off fixing the implementation of ctermid(NULL)
to return a pointer to a constant string that (per POSIX) must not be
modified by the caller, rather than needlessly copying it to another
buffer.  Then, if/when such a strcpy implementation comes up, we'll be
ready for it ;-)

Thanks,

-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer
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